Gold purity can be measured using the gold karat system, developed to measure the percentage of pure gold to other metals or alloys in jewlery. You can assess gold purity with this simple chart.

Number of Karats Parts of Gold % of Gold Purity Millesimal Fineness
9K 9/24 37.5 375
10K 10/24 41.7 416/417
12K 12/24 50.0 500
14K 14/24 58.3 583/585
18K 18/24 75.0 750
22K 22/24 91.7 916/917
24K 24/24 99.9 999

Gold Purity Conversion Chart

Source: OwlCation

Gold Purity Infographic Chart

check infographic here